As is known, many commercial and industrial activities require a fixed number of articles that are generally fed randomly and are loosely ordered and then automatically sorted so that they can thereafter be handled more easily in an automatic or semi-automatic way.
The machines designed for this operation are known as “singulators”.
The areas of use of singulators are varied, and include, by way of non-limiting example, the field of sorting and delivering mail, the dispatching and parcel distribution sector, etc.
There are several devices on the market today suitable for the performance of the above-mentioned task.
A first type of these machines comprises, in the main structure thereof intended for singulating operations, the use of a first converger station consisting of a central high-friction conveyor belt flanked on both sides by two respective roller conveyors having axes that are inclined relative to the direction of advancement of the articles.
The roller conveyors impart, to the articles resting thereon, an advancement motion and lateral translation towards the high-friction central belt, carrying the majority of articles onto the central belt itself.
Located after the converger station there is a diverger station, which is also a high-friction central belt which follows on from the central belt of the converger station and is designed to receive the articles that have been brought to the central zone of the device.
Flanking the central belt there are two roller conveyors which have rollers with inclined axes and are designed to impart to the articles entirely resting thereon an advancement motion and a corresponding lateral movement conveying them away from the high-friction central belt.
In particular, an article that might be at least partially resting on the central belt would be conveyed thereby and would not be affected by the lateral thrust of the corresponding roller conveyor; in contrast, a product resting exclusively on the roller conveyor will be conveyed away from the central belt. Appropriate conveyor belts or recirculating belts are present at the sides of the diverger station, which belts are destined to receive the products that have been conveyed away from the diverger roller conveyors and return them to the inlet of the machine and in particular to the inlet of the converger station so that they can be newly processed.
In contrast, the singulated products that are on the high-friction central belt proceed towards the further processing stations.
In this way, the products are singulated at the central zone of the machine, while all the articles which, in particular due to being superimposed in a direction that is transversal to the conveyance direction, should they not reach the central zone, are advantageously recirculated via the diverger station, and via the recirculating belts they are returned to the machine inlet and then re-processed.
U.S. Pat. No. 5,701,989 describes, with particular reference to FIG. 13, a device similar to the one described above and used in commerce.
The main difference is linked to the absence of a conveyor belt in the convergence zone (in other words there are only two roller conveyors converging towards the central advancement axis) and to the presence of a diverger station consisting of a plurality of additional conveyor belts with the aim of removing articles that are not singulated in such a way as to return them into the singulating cycle.
A second type of known devices suitable for singulating products is constituted by a complex apparatus in which all articles entering the device are suitably scanned by, for example, suitable cameras which can provide the read information to a control unit that reconstructs the distribution of the articles along the advancement pathway thereof.
In particular, a movement surface is present, consisting of an array of individual conveyor belts, all independently movable. In other words, the movement surface consists of a fixed number of rows and columns defined by a plurality of individual conveyor belts which are driven by the control unit via respective motors. As the control unit has the position of the single articles in its memory, and is monitoring the movements, it drives the conveyor belts at differentiated speeds, so as to be able to suitably orientate the articles by rotating them, and also to be able to space them apart in the longitudinal direction by differentiating the advancement speeds of the belts on which the articles are resting.
When leaving the deck, the various articles will be orientated in an orderly manner and will be sufficiently spaced along their respective advancement lines.
In this way, it will be possible to operate downstream of the surface along which the articles move, as they are already pre-ordered, and perform thereon a final singulation.
The above-mentioned machine is at least partially described in some patent publications, for example, in patents EP 1556297 and U.S. 2003/141165.
The singulators briefly described above, while admirably fulfilling the tasks they are designed for, are not free from limitations and/or operational problems.
For example, the singulators described above are not able to assure the correct singulation of articles in the event that two or more of said articles are superimposed on one another. Moreover, as regards the singulator having the converger station, the diverger station and the recirculating belt, the latter is extremely large, both longitudinally and transversally. In fact, the operating principle requires that all the products be carried on the central singulating conveyor belt, and implies the need to have predetermined lengths in the conveyance direction so as to ensure adequate filling of the high-friction central belt.
Furthermore, the need to be able to recirculate products that have not been singulated requires the presence of two further recirculating belts positioned at the sides of the machine, which obviously increases the dimensions thereof in that direction. What is described above generally implies the need to have large volumes/dimensions in order to install the singulators in question, resulting in increases in the costs of both constructing the device and managing the machine itself.
On the other hand, as the device has a multiplicity of conveyor belts that are independently movable, it is much more compact, but at the same time, extremely complex in terms of the construction and management of the operation thereof.
Indeed, it is necessary to set up a control unit and cameras to monitor the movement of the articles, as well as a control algorithm that can enable efficient and individual operation in a controlled manner on each of the conveyor belts.
Furthermore, each of the conveyor belts is equipped with a respective drive and a respective motor, which clearly increase the costs of construction and maintenance, while at the same time reducing the reliability of the singulator (considering the high number of electrical and mechanical parts that make it up).